title: The cell-end marker TeaA and the microtubule polymerase AlpA contribute to microtubule guidance at the hyphal tip cortex of Aspergillus nidulans to provide polarity maintenance.
abstract: In the absence of landmark proteins, hyphae of Aspergillus nidulans lose their direction of growth and show a zigzag growth pattern. Here, we show that the cell-end marker protein TeaA is important for localizing the growth machinery at hyphal tips. The central position of TeaA at the tip correlated with the convergence of the microtubule (MT) ends to a single point. Conversely, in the absence of TeaA, the MTs often failed to converge to a single point at the cortex. Further analysis suggested a functional connection between TeaA and AlpA (an ortholog of the MT polymerase Dis1/CKAP5/XMAP215) for proper regulation of MT growth at hyphal tips. AlpA localized at MT plus-ends, and bimolecular fluorescence complementation assays suggested that it interacted with TeaA after MT plus-ends reached the tip cortex. In vitro MT polymerization assays showed that AlpA promoted MT growth up to sevenfold. Addition of the C-terminal region of TeaA increased the catastrophe frequency of the MTs. Thus, the control of the AlpA activity through TeaA might be a novel principle for MT growth regulation after reaching the cortex. In addition, we present evidence that the curvature of hyphal tips also could be involved in the control of MT growth at hyphal tips.
authors.affiliation: Karlsruhe Institute of Technology, Department of Microbiology, Hertzstrasse 16, 76187 Karlsruhe, Germany.
authors.forename: Norio
authors.initials: N
authors.lastname: Takeshita
authors.forename: Daniel
authors.initials: D
authors.lastname: Mania
authors.forename: Saturnino
authors.initials: S
authors.lastname: Herrero
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishitsuka
authors.forename: G Ulrich
authors.initials: GU
authors.lastname: Nienhaus
authors.forename: Marija
authors.initials: M
authors.lastname: Podolski
authors.forename: Jonathon
authors.initials: J
authors.lastname: Howard
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fischer
mesh_terms: D001233:Aspergillus nidulans / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D016764:Cell Polarity; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005816:Genetic Complementation Test; D025301:Hyphae / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism; D008870:Microtubules / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D058105:Polymerization; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins; D011994:Recombinant Proteins
keywords: AlpA; Aspergillus nidulans; Cell-end marker; Hyphal tip; Microtubule; Polarity; TeaA; XMAP215